Marine Weather and Tide Forecast for San Lorenzo, CA

SHORT TERM
Issued at 1210 AM PDT Mon Jul 14 2025 (Today and tonight)

Satellite imagery depicts the coastal stratus layer streaming into the Sonoma County valleys, curling from the East Bay across the southern San Francisco Bay, and blanketing the Monterey Bay region and Salinas Valley. Expect some additional inland stratus development through the rest of the morning before the clouds retreat to the immediate coast after sunrise. The temperature forecast will feel like a bit of deja vu from the last couple of days, with low temperatures this morning ranging from the middle to upper 50s across the lower elevations and the 60s to lower 70s in the higher elevations. Meanwhile, high temperatures range from the 80s to the lower 90s inland with temperatures near 100 in the warmest spots, the 70s and lower 80s near the Bays, and the upper 50s to lower 60s along the Pacific Coast. Breezy onshore winds develop in the afternoon and evening with wind gusts up to 25 mph through favored gaps and passes and within the Salinas Valley.

Localized elevated fire weather threat continues across areas above and inland of the marine layer's influence. The combination of dry daytime humidities of around 20-35%, poor overnight recoveries of 25- 40%, and localized gusts to 25 mph will be the main factors behind the elevated threat. However, the winds will remain onshore, leading to the fire weather threat being diurnally driven, especially in the foothills where lighter winds and good overnight recoveries are expected each night.

LONG TERM
Issued at 1210 AM PDT Mon Jul 14 2025 (Tuesday through Sunday)

Late today, a shortwave trough, or perhaps a weak cutoff low, develops into the Pacific Northwest and the northern Rockies, pushing the ridge axis towards the west and north and causing a noticeable cooling trend to begin tomorrow and lasting for the following two days. High temperatures drop into the middle 70s to middle 80s inland and the upper 60s to the middle 70s along the Bayshore, with the coast remaining rather stable at the upper 50s to lower 60s.

A slight warming trend is expected heading towards the upcoming weekend. Ensemble model cluster analysis does feature scenarios where troughing and ridging develop over the northwestern United States through the upcoming weekend. However, in terms of sensible weather, most of the impacts from any deviation in the weather pattern will be felt across the Pacific Northwest and northern Rockies, with muted impacts across central California. Although the exact details are still subject to variation, the current forecast sees temperatures across the inland valleys rising to the 80s and lower 90s, up to the upper 90s in the warmest locations.

AVIATION
(06Z TAFS)
Issued at 1011 PM PDT Sun Jul 13 2025

The onshore SFO-SAC 3.2 mb predominates with decent inland stratus and fog intrusion potential tonight and Monday morning.
Over the CA coastal waters and offshore waters a weak and nearly stationary surface trough persists. Coastal profilers from Bodega Bay to Point Sur show very little change in the marine layer depth, varying from 1300 to 1500 feet. Recent air temps at San Francisco downtown and Oakland downtown are ~ 1/2 degree Fahrenheit cooler than this time 24 hours ago, it may not sound like much and it isn't, but it may represent a slight change in surface air mass characteristics advected in from the coastal waters. The overall combination of a clear sky above the marine layer with this evening's 00z Oakland sounding precipitable water lower at 0.51" (10th percentile for time of year) supports improved nocturnal radiational cooling which while there is a surface influx of slightly cooler air within the marine layer may set up for a longer duration stratus and fog intrusion to mix out Monday. For the 06z TAFs decided to slightly extend ceiling forecasts over model output by an hour or two.

Only minor temperature fluctuations are forecast aloft specifically in the vicinity of 925 mb (~ 2500 feet) tonight and Monday. Thermal ridging aloft otherwise continues in the lower to mid levels tonight and Monday. The 06z TAFs still mainly lean toward persistence, expect an ongoing inland intrusion of stratus, patchy fog and redevelopment of at least patchy light coastal drizzle /IFR-LIFR/ tonight and Monday morning. Lower level temps at ~ 2500 feet begin to cool Monday night with 2 Celsius to 3 Celsius cooling by 12z Tuesday morning per 18z NAM output. Lower level cool air advection should begin to deepen the marine layer setting up for a deeper inland stratus intrusion Monday night and Tuesday morning.

Vicinity of SFO...Amended the earlier TAF forecast to extend VFR conditions just a little longer tonight, satellite imagery shows stratus curling around from the Golden Gate to Oakland, a classic summer set up for later arrival at SFO. Forecast tempo IFR 08z-10z, then IFR prevailing. RAP model is indicating high humidity, low ceiling and fog potential tonight/Monday morning. Conditions may not lift to MVFR-VFR until Monday early afternoon. West-northwest wind tonight. West to northwest wind becoming gusty to 25 knots Monday afternoon and evening. Stratus returns Monday evening and night.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Stratus, fog and drizzle /IFR-LIFR/ tonight and Monday morning. Conditions lifting to MVFR-VFR Monday afternoon.
Stratus returns early Monday evening and night. Onshore winds 5 to 15 knots.

MARINE
(Tonight through next Friday)
Issued at 441 PM PDT Sun Jul 13 2025

Localized hazardous marine conditions in the form of strong northerly breezes and very rough seas will be present Monday and Tuesday for the northern outer waters. Aside from that, a gentle to moderate breeze with moderate to rough seas will prevail through Thursday.

MTR WATCHES/WARNINGS/ADVISORIES
CA...None.
PZ...Small Craft Advisory from 3 PM this afternoon to 3 PM PDT Tuesday for Pt Arena to Pt Reyes 10-60 NM.